Chosen by the Church's god, Origin, a young country girl named Flum Apricot is enlisted in the hero's party and expected to fight demons. However, her one innate skill, Reversal, has no practical use, and the party's sage, Jean Inteige, treats her as a burden, eventually selling her off to a slave dealer.

In the slave dealer's dark dungeon, all hope seems lost. But in a moment of desperation, Flum discovers that her skill actually turns the negative energy of cursed weapons into power, which helps her slay the slave owner and escape with another captured girl, Milkit. Now equipped with the means to fight and survive, Flum embraces the career of an adventurer and aims to lead a happy life with Milkit, away from the grim machinations of the Church.